This invention relates to PIP (picture-in-picture) arrangements in television receivers and in particular to the use of the PIP circuitry to enable a fast, simple one key operation for freezing the frame of video that is currently being displayed.
In many instances, it is desirable to be able to "freeze" or "take a snapshot" of the video being displayed on the viewing screen of a television receiver. This feature is especially valuable when the display includes textual material or a telephone number that the viewer wishes to carefully read, or otherwise take further note of The PIP circuitry has been used to freeze the video being displayed, albeit in a cumbersome manner that requires operation of multiple keys on a remote control keypad. Some systems only freeze the PIP display, which is accomplished by operating a freeze button, for example, while the PIP circuitry is activated. Since the PIP display is generally viewed on a monitoring basis, there is rarely a desire to freeze its display. Even then, the frozen video display is likely to be too small to be useful, since as mentioned, the PIP picture is generally used for monitoring and is most likely to be a small display to minimize any distraction from the main television picture. To obtain a useful size frozen picture or snapshot, the viewer would need to expand the PIP display to one of the larger sizes, which involves additional key operations as well as loss of time. There is also the likelihood that the main video display that the viewer desires to freeze will have changed by then.
One prior art system enables the main screen video to be frozen in a PIP display by depressing a freeze key when PIP is not active. The system operates to change the source inputs established by the viewer, e.g., antenna/cable to main input and VCR to PIP input, so that the antenna/cable is connected to the PIP input. The frozen PIP display is removed by operating the PIP button. Not only are two different buttons required in the sequence, but the viewer must return to the setup menu and change the PIP input to VCR to revert to the PIP operation that was established before the freeze button was operated. (Failure to change the PIP input setting results in the main picture being replicated in the PIP display.) On the other hand, if the freeze button is depressed when normal PIP is operating, the normal PIP display is frozen. The arrangement causes viewer confusion since different things happen when the freeze key is operated, depending upon the PIP operating condition, and also since multiple keys are involved. Further, the PIP display size (with the frozen main picture) corresponds to the display size of the PIP the last time it was activated, which most likely is the smallest size PIP available.
As is readily seen from the above, the prior art has many limitations in enabling a viewer to simply and quickly freeze or take a snapshot of the main video display currently being viewed. The invention provides a simple and low cost method of accomplishing this highly desirable end.